Research samples from families with genetic diseases: a proposed code of conduct.

Research on samples from families with genetic disease underlies many of the major advances that are occurring in medical genetics. But ethical and practical problems may arise when samples from relatives who are healthy but at risk are included in such studies. In particular, new molecular tests for specific gene mutations may result in the detection of a genetic defect in relatives who had neither expected this possibility nor given specific consent to such testing. Family members at risk should not be included in such studies unless strictly necessary, and in such cases specific consent should be obtained and information should be given about the implications of an abnormal result of a test. This is particularly important when stored samples from previous studies without such implications are being reused and is also relevant to the genetic testing of samples taken primarily for epidemiological studies of disorders when only a small proportion of cases is thought to be genetic in origin. There is a need for guidelines to protect both subjects and investigators in a field which is spreading rapidly and involving many clinical and laboratory research workers previously unfamiliar with genetic testing.